/Engine/Plugins/Developer/Concert/ConcertSync/ConcertSyncClient/Source/ConcertSyncClient/Public/IConcertSyncClient.h
Get the delegate called just after the workspace gets deleted.
[FOnConcertClientSyncSessionStartupOrShutdown](API\Plugins\ConcertSyncClient\FOnConcertClientSyncSessionStart-) & OnSyncSessionShutdown()